The present invention pertains to intraosseous dental implants and more specifically to a prosthetic device for such implants.
Intraosseous or osteointegrated dental implants usually comprise an implant (fixture), which is implanted in the bone in order to be integrated with it, and a prosthetic intraplantar pin having a transmucosa connection (abutment), to which the dental prosthesis is fixed. Currently, if it is used, the intraplantar pin is screwed and/or cemented directly in the implant with a male/female coupling in order to thus form a complete integral unit. However, this mode of fixation of the intraplantar pin poses many problems.
In fact, if the pin is simply screwed, given the forces to which the prosthesis is subjected, the pin tends to unscrew with the result of making possible rotational movements and even accidental disconnections of the prosthesis which then require interventions for repairing the fixation. In other words, the stability of the prosthesis may be precarious. On the other hand, if the pin is cemented, it becomes difficult to remove. In both cases then, such a fixation makes the search for parallelization of the elements difficult, and moreover, the resulting composition is highly rigid both in terms of its structure and in terms of its behavior under force, conditions which may cause damage to the bone and which, at any rate, do not correspond to the elastic, or cushioned, connection, as exists between a natural tooth and bone.
The object of the present invention is to eliminate or at least to reduce the above mentioned problems mainly by means of:
the search for a balance between stability and reversibility of the fixation, so as to ensure both with elements of a novel and original combination;
the achievement of a paraphysiological, xe2x80x9ccushionedxe2x80x9d dental prosthesis, which reproduces the characteristics of a connection between a natural tooth and bone so as not to stress and damage the bone;
the elimination of rotational movements and/or of accidental disconnections to reduce the need for repair interventions;
ease of insertion of bridge-type prostheses even for unparallel implants up to 60xc2x0;
ease and precision of the taking of impressions by means of so-called xe2x80x9ccopying pick-up,xe2x80x9d in the absence of a xe2x80x9cpulling effectxe2x80x9d of the impression;
reduction in the lateral tensile forces typical of the rigid systems both on the xe2x80x9cfixturexe2x80x9d and on the components of the prosthesis, the tightening screw in particular, thanks to the cushioning and to the washer made of plastic material;
the easy removability of the intraplantar pin by means of a screw-type extractor coaxial to the implant.
This object is accomplished with a prosthetic device for intraosseous dental implants comprising an intraosseous support implant and an intraplantar pin. The support implant has a blind cavity, which is open towards the top of the implant and has at least one internal zone with a conical surface. The intraplantar pin has a shank intended to be implanted and to be blocked in the cavity of the support implant and a transmucosa connection head lying above the implant. The shank has at least one conical external zone of forced coupling with the conical internal zone of the cavity of the support implant. A cap for a dental prosthesis is fixed to the connection head with the interposition of a semirigid cushioning ring.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.